This invention relates to downhole anchoring tools, and more particularly to a well bore anchor that may be used for stabilizing a sand cutter and similar equipment in the well bore during a cutting operation.
In well operations, sometimes a well must be abandoned and plugged. The government regulations require that a casing be cut at a certain depth below the surface. Sand cutters have been conventionally used for performing the cutting operation. It was noted that when the cutting is performed at the depth of about 100 feet, the pressures downhole tend to push and excite the nozzle of the sand cutter and move it out of alignment by a small distance, such as a quarter of an inch. However, this small distance is critical in the tight confines of a casing. The string supporting the cutter is energized and causes it to move from the required alignment. As a result, the cut created by the sand cutter is no longer circular but rather resembles a spiral, such that the end of the cut does not necessary meet the beginning of the cut.
The deeper the casing cutting operations are performed, the more pronounced the problem becomes. With deeper wells, more hydraulic lines need to be run, more feed of the pipes downhole, and more possibility of misalignment. One of the solutions was to place a centralizing plate around the cutting tool to keep the cutter from moving into misalignment. However, the centralizing plate has to be carefully inserted and then properly aligned at the desired depth. Even then, a possibility exists for the hydraulic force imparted on the cutter to unseat the plate, which will result in an uneven cut.
The present invention contemplates elimination of drawbacks associated with the prior art and provision of an anchoring tool, which positively engages the inner walls of the casing allowing a cutting tool, or other necessary equipment to be securely connected to the top or bottom of the tool for performing the required operations in the well bore.